HOT: Active* forum members generally gain 5% discount at starbike.com store!
Weight Weenies
* FAQ    * Search    * Trending Topics
* Login   * Register
HOME Listings Articles FAQ Contact About




Post new topic Reply to topic  [ 6 posts ] 
Author Message
PostPosted: Mon Jun 03, 2013 8:05 am 
Offline

Joined: Wed Dec 14, 2011 8:20 pm
Posts: 175
So I have a Scott Foil, which is a frame with PF86 BB standart. I wanted to have a power meter in near future and got my hands on a Rotor 3D+ crank for a reasonable price. I could now install Power2Max power meter, but I ran to an issue with the plain crank first.
Rotor 3D+ is a crank with 30mm spindle, PF86 standart accepts cranks with 24mm spindle. That's a mismatch, but Rotor has made available BB cups which go into a 41mm diameter PF86 frame and accept a 30mm spindle (http://www.bike24.com/1.php?content=8;n ... duct=34356). So looks like problem solved.

I installed the Rotor 4130 cups and then the crank. The spindle was pre-attached to the NDS crankarm. I put on the DS arm and tightened the center bolt to 30Nm. I used the compression ring to adjust the preload.
Now, when I'm on the small chainring, I can't use three smaller sprockets. The lower I go, the more chain starts to rub against the big chainring and on 38-11 the chain wants to switch itself to the big chainring without actually changing the gear. It helped a little when I put a 2mm washer behind the DS crank and removed the plastic washer from the NDS so it would sit more outward.
I wouldn't mind if the problem was with just the smallest sprocket, but three are just too much for a solution that should work.
Also, when on the big chainring, the chainline looks different when compared to my old Shimano crank. Currently, the chainline is straight on one or two sprockets higher. I'll go to my LBS today and compare to a stock Foil, but it seems to me that somebody has forgot something when this solution was developed.

_________________
Scott Foil Di2 2012
Scott Scale 35 2010


Top
 Profile  
 
Posted: Mon Jun 03, 2013 8:05 am 


Top
  
 
PostPosted: Tue Jun 04, 2013 12:26 pm 
Offline
Shop Owner

Joined: Sat Jun 13, 2009 4:02 am
Posts: 1951
Location: NoVA/DC
What cranks were you coming from? Shimano?

Sent from my EVO using Tapatalk 4 Beta


Top
 Profile  
 
PostPosted: Wed Jun 05, 2013 9:10 am 
Offline

Joined: Wed Dec 14, 2011 8:20 pm
Posts: 175
Yes, DA7900

_________________
Scott Foil Di2 2012
Scott Scale 35 2010


Top
 Profile  
 
PostPosted: Wed Jun 05, 2013 9:25 am 
Offline
Moderator
User avatar

Joined: Sat Mar 14, 2009 6:08 am
Posts: 7318
Location: Geeeelong!
Found this exact issue on bikes I have tested with Shimano and Rotor chainrings.

The problem seems to lie with the cranks, as it happened on a Fuji and a Cervelo.

_________________
Baum Ristretto, Baum Mondrian Corretto & the '89 Merckx! | "If you could eat it in one sitting, hold your line." | twitter.com/Tinea_Pedis


Top
 Profile  
 
PostPosted: Sun Jun 09, 2013 5:05 pm 
Offline
Shop Owner

Joined: Sat Jun 13, 2009 4:02 am
Posts: 1951
Location: NoVA/DC
It's the rings. but it's technically not a "problem", more of a "characteristic".
I described the issue earlier here:
viewtopic.php?t=116422
HELP! problems with Praxis rings on SISL chainset

Sent from my EVO using Tapatalk 4 Beta


Top
 Profile  
 
PostPosted: Mon Jun 10, 2013 12:37 pm 
Offline

Joined: Wed Dec 14, 2011 8:20 pm
Posts: 175
The gap difference between DA7900 crankset chainrings and Rotor crankset chainrings is very small, maybe a 1mm max (hard to measure exactly). However, the big ring on DA7900 crank does lean outward, which allows for more cross chaining.
I already had a 1,3mm spacer but I added an extra 3,6mm spacer between the DS crank and BB. I can now use all but the smallest sprocket and the second smallest sprocket is slightly rubbing against the big chainring on the bottom where there is less tension on the chain. It totals up to 4,9mm of spacer. That can't be a problem of chainring only. That is more of a design problem or a very product information.

_________________
Scott Foil Di2 2012
Scott Scale 35 2010


Top
 Profile  
 
Posted: Mon Jun 10, 2013 12:37 pm 


Top
  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 6 posts ] 


Who is online

Users browsing this forum: csf, jooo, RimClencher, rmerka and 47 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

   Similar Topics   Author   Replies   Views   Last post 
There are no new unread posts for this topic. Rotor Flow vs Rotor 3D+ 2014

in Road

IchDien

8

1398

Thu Jan 16, 2014 7:15 pm

IchDien View the latest post

There are no new unread posts for this topic. Rotor 3DF 52/36 To 50/34

in Road

ramchip

2

675

Tue Sep 03, 2013 1:13 pm

NiFTY View the latest post

There are no new unread posts for this topic. Would you go Rotor 3D or 3DF/+ ?

in Road

davidalone

3

486

Tue Feb 25, 2014 12:07 am

wpccrunner View the latest post

There are no new unread posts for this topic. 2014 Rotor 3d+

in Road

drainyoo

9

1285

Tue Feb 04, 2014 2:43 am

743power View the latest post

There are no new unread posts for this topic. Ryder's Rotor SRM

in Road

dalex

10

2058

Sat May 11, 2013 6:15 pm

dalex View the latest post


It is currently Mon Apr 21, 2014 2:51 pm

All times are UTC + 1 hour




Advertising   –  FAQ   –  Contact   –  Convert   –  About

© Weight Weenies 2000-2013
hosted by starbike.com


How to get rid of these ads? Just register!


Powered by phpBB